EP4317720A1 - Multi-row bearing and bearing unit - Google Patents
Multi-row bearing and bearing unit Download PDFInfo
- Publication number
- EP4317720A1 EP4317720A1 EP22780945.6A EP22780945A EP4317720A1 EP 4317720 A1 EP4317720 A1 EP 4317720A1 EP 22780945 A EP22780945 A EP 22780945A EP 4317720 A1 EP4317720 A1 EP 4317720A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- groove
- axial direction
- outer ring
- ring raceway
- inner ring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000000149 penetrating effect Effects 0.000 claims description 4
- 238000005259 measurement Methods 0.000 description 9
- 230000002093 peripheral effect Effects 0.000 description 9
- 238000003754 machining Methods 0.000 description 8
- 229910000831 Steel Inorganic materials 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C19/00—Bearings with rolling contact, for exclusively rotary movement
- F16C19/02—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows
- F16C19/14—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load
- F16C19/18—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with two or more rows of balls
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C19/00—Bearings with rolling contact, for exclusively rotary movement
- F16C19/02—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows
- F16C19/04—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly
- F16C19/08—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly with two or more rows of balls
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C19/00—Bearings with rolling contact, for exclusively rotary movement
- F16C19/54—Systems consisting of a plurality of bearings with rolling friction
- F16C19/56—Systems consisting of a plurality of bearings with rolling friction in which the rolling bodies of one bearing differ in diameter from those of another
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C31/00—Bearings for parts which both rotate and move linearly
- F16C31/04—Ball or roller bearings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C43/00—Assembling bearings
- F16C43/04—Assembling rolling-contact bearings
- F16C43/06—Placing rolling bodies in cages or bearings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
- F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
- F16H25/20—Screw mechanisms
- F16H25/22—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members
- F16H25/2204—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members with balls
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
- F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
- F16H25/20—Screw mechanisms
- F16H25/24—Elements essential to such mechanisms, e.g. screws, nuts
Definitions
- the present invention relates to a multi-row bearing and a bearing unit, and more particularly, to a multi-row bearing and a bearing unit in which an axial dimension between raceway grooves of the multi-row bearing can be easily and accurately measured so that the raceway grooves can be machined with high accuracy.
- Patent Literature 1 discloses a multi-row bearing having multiple rows of raceway grooves in inner and outer rings of a bearing, in which each raceway groove of the inner ring is formed over groove shoulders on both sides in an axial direction of the raceway groove, and each raceway groove of the outer ring is formed over a groove shoulder on one side in the axial direction of the raceway groove.
- a thrust and radial bearing is disclosed in which the inner ring is inserted into the outer ring, balls are inserted between raceway grooves from a radial hole opened in the outer ring, and then the outer ring is moved in the axial direction to be assembled.
- raceway groove machining of such a multi-row bearing, it is required that axial dimensions of the raceway grooves of the inner ring and the outer ring coincide with each other, and therefore the raceway grooves are machined while measuring the axial dimension between the raceway grooves and adjusting the axial dimension between the raceway grooves to a target dimension. Accordingly, the measurement is usually performed many times during machining, and therefore it is required that the measurement can be easily and accurately performed at a short time.
- the measurement cannot be performed by a simple method, a workpiece is once removed from a processing machine and measured, and the workpiece is again attached to the processing machine to be machined, which is not preferable because the processing method requires very cost and labor.
- the measuring tool 50 As a measuring tool that can easily perform the measurement at a short time, for example, there is a measuring tool 50 having a structure illustrated in FIGS. 3A and 3B . As will be described in detail later, the measuring tool 50 is configured such that the measuring tool 50 is stably held by engaging a pair of steel balls 55, 56 with a raceway groove serving as a measurement reference, and then an axial distance between the raceway grooves is measured by pressing a gauge head 57 against a raceway groove to be measured.
- the reference raceway groove is preferably formed on both sides of a groove bottom.
- Patent Literature 1 JPH04-262120A
- the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a multi-row bearing and a bearing unit including the multi-row bearing in which an axial dimension between raceway grooves can be accurately and easily measured at a short time, and the raceway grooves can be further machined with high dimensional accuracy.
- the axial dimension between the raceway grooves can be accurately and easily measured at a short time, and accordingly, the raceway grooves of the multi-row bearing having high dimensional accuracy between the raceway grooves and stable quality can be machined.
- FIG. 1 is a cross-sectional view illustrating a state before a multi-row bearing according to a first embodiment of the present invention is assembled
- FIG. 2 is a cross-sectional view illustrating a state after the multi-row bearing is assembled.
- a left direction and a right direction in the drawings are referred to as one side and the other side, respectively.
- a bearing unit 100 includes a multi-row bearing 10 and a ball screw mechanism 40 using an inner ring 30 of the multi-row bearing 10 as a nut.
- the multi-row bearing 10 includes an outer ring 20 having three rows of outer ring raceway grooves 21a, 21b, and 21c on an inner peripheral surface thereof, an inner ring 30 having three rows of inner ring raceway grooves 31a, 31b, and 31c on an outer peripheral surface thereof, and a plurality of balls 45 disposed between the outer ring raceway grooves 21a, 21b, and 21c and the inner ring raceway grooves 31a, 31b, and 31c so as to be rollable between the outer ring raceway grooves 21a, 21b, and 21c and the inner ring raceway grooves 31a, 31b, and 31c.
- the outer ring raceway groove 21a formed at an end portion on the other side in an axial direction of the outer ring 20 is formed over groove shoulders on both sides in the axial direction.
- the outer ring raceway groove 21a is formed in left-right line symmetry with respect to a groove bottom.
- the two outer ring raceway grooves 21b, 21c formed at an intermediate portion in the axial direction and an end portion on one side in the axial direction of the outer ring 20 are each formed over a groove shoulder on the one side (the other side) in the axial direction from a groove bottom.
- the raceway grooves 21b, 21c are formed only on the other side with respect to the groove bottom. That is, the outer ring raceway groove 21a has a raceway groove having a substantially semicircular cross section, and the outer ring raceway grooves 21b, 21c each have a raceway groove having a substantially 1/4 circular cross section formed on the other side of the outer ring 20.
- a cylindrical surface 21e continuous from the groove bottom of the outer ring raceway groove 21b is formed between the outer ring raceway groove 21b and the outer ring raceway groove 21c. Further, a cylindrical surface 21f continuous from the groove bottom of the outer ring raceway groove 21c is also formed on one side in the axial direction of the outer ring raceway groove 21c. An inner diameter of the groove bottom of the outer ring raceway groove 21b and an inner diameter of the cylindrical surface 21e, and an inner diameter of the groove bottom of the outer ring raceway groove 21c and an inner diameter of the cylindrical surface 21f are substantially the same.
- the cylindrical surface 21e is provided with an opening portion 22 penetrating in a radial direction.
- the inner diameters of the cylindrical surfaces 21e, 21f may be different from the inner diameters of the outer ring raceway grooves 21b, 21c as long as the cylindrical surfaces 21e, 21f do not interfere with balls when the balls are assembled as described later.
- the inner ring 30 is also a nut of the ball screw mechanism 40 as will be described later, and is a divided inner ring including a substantially bottomed cylindrical inner ring main body 31 that is long in the axial direction and has a bottomed hole 34 having a bottom portion 33 at the end portion on the other side, and a pressing lid 32.
- the inner ring raceway groove 31a formed at end portion on one side of the inner ring main body 31 is formed over groove shoulders on both sides in the axial direction. Specifically, the inner ring raceway groove 31a is formed in left-right line symmetry with respect to a groove bottom.
- the inner ring raceway groove 31b formed at an intermediate portion in the axial direction of the inner ring 30 extends from a groove bottom to the groove shoulder on the one side (one side) in the axial direction. Specifically, the raceway groove is formed only on one side with respect to the groove bottom.
- a cylindrical surface 31f continuous from the groove bottom of the inner ring raceway groove 3 1b is formed on the other side of the inner ring raceway groove 31b.
- An outer diameter of the groove bottom of the inner ring raceway groove 31b and an outer diameter of the cylindrical surface 31f are substantially the same.
- the inner diameter of the cylindrical surface 31f may be different from the inner diameter of the inner ring raceway groove 31b as long as the cylindrical surface 31f does not interfere with balls when the balls are assembled as described later.
- the pressing lid 32 is a member fixed to the inner ring main body 31 to form the inner ring raceway groove 31c, and a raceway groove having a substantially 1/4 circular cross section and serving as the inner ring raceway groove 31c is formed in an outer diameter corner portion on one side. Further, the pressing lid 32 is provided with a screw hole 36 through which a bolt (not illustrated) for screwing into a female screw 35 provided at the bottom portion 33 of the inner ring main body 31 to fix the pressing lid 32 to the inner ring main body 31 is inserted.
- a ball screw groove 41 (nut-side ball screw groove) of the ball screw mechanism 40 is formed on an inner peripheral surface of the bottomed hole 34 of the inner ring main body 31, and a ball screw shaft 43 formed with a ball screw groove 42 (screw shaft-side ball screw groove) formed on an outer peripheral surface thereof is rotatably accommodated in the bottomed hole 34.
- a plurality of balls are disposed between the ball screw groove 41 of the inner ring main body 31, that is, the nut and the ball screw groove 42 of the ball screw shaft 43 so as to be freely rotatable therebetween.
- the bearing unit 100 is formed by combining the ball screw mechanism 40 including the inner ring main body 31, which is provided with the ball screw groove 41 on the inner peripheral surface and functions as the nut of the ball screw mechanism 40, the ball screw shaft 43, and the balls (not illustrated) with the multi-row bearing 10.
- the outer ring 20 is placed on the inner ring 30 in a state of being slightly shifted to the other side. In this state, the opening portion 22 of the outer ring 20 is positioned corresponding to the inner ring raceway groove 31b.
- the plurality of balls 45 are loaded between the inner ring raceway groove 31a and the cylindrical surface 21f of the outer ring 20 from one side.
- the plurality of balls 45 are loaded between the inner ring raceway groove 31b and the cylindrical surface 21e from the opening portion 22. Further, the plurality of balls 45 are loaded into the outer ring raceway groove 21a from the other side, and are pressed by the pressing lid 32.
- the outer ring 20 is slid to one side together with the pressing lid 32, gaps between the balls 45 and the outer ring raceway groove 21a and the inner ring raceway groove 31c are adjusted to a predetermined value by the pressing lid 32, a bolt (not illustrated) inserted into the screw hole 36 of the pressing lid 32 is screwed into the female screw 35, and the pressing lid 32 is fixed to the inner ring main body 31.
- the plurality of balls 45 are disposed between the respective raceway grooves, that is, between the inner ring raceway groove 31a and the outer ring raceway groove 21c, between the inner ring raceway groove 31b and the outer ring raceway groove 21b, and between the inner ring raceway groove 31c and the outer ring raceway groove 21a so as to be rollable therebetween, whereby the multi-row bearing 10 of three rows are assembled.
- the ball screw shaft 43 moves in the axial direction relative to the inner ring 30.
- a load P indicated by an arrow in the drawing acts on the ball screw shaft 43. Since the load P is received by the multi-row bearing 10 having multiple rows of raceway grooves, the large load P can be supported.
- the inner ring raceway grooves 31a, 31b, and 31c are formed on an outer peripheral side of the inner ring 31, comparative measurement and machining are easy, but since the outer ring raceway grooves 21a, 21b, and 21c are formed on an inner peripheral side of the outer ring 20, the outer ring raceway grooves 21a, 21b, and 21c are difficult to be machined, and it is necessary to machining the raceway grooves while measuring and adjusting the axial dimension between the raceway grooves. Accordingly, the dimension measurement between the raceway grooves needs to be performed many times during machining, and the measuring tool is required to be able to perform the measurement easily and accurately at a short time.
- the axial dimension between the raceway grooves is measured by a dedicated measuring tool 50 as illustrated in FIGS. 3A and 3B .
- a dedicated measuring tool 50 as illustrated in FIGS. 3A and 3B .
- a case where an axial dimension between raceway grooves of the outer ring 20 is measured will be described as an example.
- the measuring tool 50 includes a fixed arm 52 fixed to a support shaft 51, a movable arm 53 swingable about the support shaft 51, and a measuring arm 54 provided to be slidable with respect to the fixed arm 52.
- Steel balls 55, 56 having the same size as the balls 45 used in the multi-row bearing 10 are attached to distal ends of the fixed arm 52 and the movable arm 53, and a gauge head (steel ball) 57 having the same size as the balls 45 used in the multi-row bearing 10 is similarly attached to a distal end of the measuring arm 54.
- the steel balls 55, 56 of the fixed arm 52 and the movable arm 53 are fitted into the pair of outer ring raceway grooves 21a of the outer ring 20 facing each other, and the measuring tool 50 is stably held. That is, the outer ring raceway groove 21a of the outer ring 20 whose raceway groove is formed on both sides with respect to the groove bottom serves as a reference groove for measuring a distance between the raceway grooves.
- the movable arm 53 is extended and contracted in an arrow direction to engage the gauge head 57 with the outer ring raceway groove 21b or 21c to be measured, and the axial dimension between the raceway grooves is measured from a movement distance of the measuring arm 54.
- the outer ring raceway grooves 21b, 21c can be accurately machined with reference to the outer ring raceway groove 21a.
- the multi-row bearing 10 according to a second embodiment of the present invention will be described with reference to FIGS. 4 and 5 .
- four rows of outer ring raceway grooves 21a, 21b, 21c, and 21d are formed on the inner peripheral surface of the outer ring 20
- four rows of inner ring raceway grooves 31d, 31c, 31b, and 31a are formed on the outer peripheral surface of the inner ring 30 so as to face the outer ring raceway grooves 21a, 21b, 21c, and 21d.
- the outer ring raceway grooves 21a, 21b, 21c, and 21d of the outer ring 20 are respectively formed with cylindrical surfaces 21e continuous from the groove bottoms of the outer ring raceway grooves 21b, 21c, and the two cylindrical surfaces 21e are provided with the opening portions 22 penetrating in the radial direction.
- the axial dimension between the raceway grooves can be accurately measured at a short time by the measuring tool 50 illustrated in FIG. 3 with reference to the outer ring raceway groove 21a. Accordingly, the other outer ring raceway grooves 21b, 21c, and 21d can be accurately machined with reference to the outer ring raceway groove 21a.
- a method for assembling the outer ring 20, the inner ring 30, and the plurality of balls 45 is the same as that of the multi-row bearing 10 according to the first embodiment in that the ball screw mechanism 40 is configured by using the inner ring 30 as the nut and disposing the ball screw shaft 43 inside the nut.
- the multi-row bearing 10 according to the second embodiment has four rows of raceway grooves, it is possible to support a larger load than the multi-row bearing 10 according to the first embodiment.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Rolling Contact Bearings (AREA)
Abstract
Provided are a multi-row bearing and a bearing unit including the multi-row bearing in which an axial dimension between raceway grooves can be accurately and easily measured at a short time, and the raceway grooves can be further machined with high dimensional accuracy. In a multi-row bearing (10), an inner ring raceway groove (31a) at one end portion in an axial direction is formed over groove shoulders on both sides in the axial direction with respect to a groove bottom, and an inner ring raceway groove (31b) at an intermediate portion in the axial direction is formed over a groove shoulder on one side in the axial direction from a groove bottom. In addition, an outer ring raceway groove (21a) at the other end portion in the axial direction is formed over groove shoulders on both sides in the axial direction with respect to a groove bottom, and an outer ring raceway groove (21b) at the intermediate portion in the axial direction is formed over a groove shoulder on one side in the axial direction from a groove bottom.
Description
- The present invention relates to a multi-row bearing and a bearing unit, and more particularly, to a multi-row bearing and a bearing unit in which an axial dimension between raceway grooves of the multi-row bearing can be easily and accurately measured so that the raceway grooves can be machined with high accuracy.
- Patent Literature 1 discloses a multi-row bearing having multiple rows of raceway grooves in inner and outer rings of a bearing, in which each raceway groove of the inner ring is formed over groove shoulders on both sides in an axial direction of the raceway groove, and each raceway groove of the outer ring is formed over a groove shoulder on one side in the axial direction of the raceway groove. In addition, a thrust and radial bearing is disclosed in which the inner ring is inserted into the outer ring, balls are inserted between raceway grooves from a radial hole opened in the outer ring, and then the outer ring is moved in the axial direction to be assembled.
- In raceway groove machining of such a multi-row bearing, it is required that axial dimensions of the raceway grooves of the inner ring and the outer ring coincide with each other, and therefore the raceway grooves are machined while measuring the axial dimension between the raceway grooves and adjusting the axial dimension between the raceway grooves to a target dimension. Accordingly, the measurement is usually performed many times during machining, and therefore it is required that the measurement can be easily and accurately performed at a short time. When the measurement cannot be performed by a simple method, a workpiece is once removed from a processing machine and measured, and the workpiece is again attached to the processing machine to be machined, which is not preferable because the processing method requires very cost and labor.
- As a measuring tool that can easily perform the measurement at a short time, for example, there is a
measuring tool 50 having a structure illustrated inFIGS. 3A and 3B . As will be described in detail later, themeasuring tool 50 is configured such that themeasuring tool 50 is stably held by engaging a pair ofsteel balls gauge head 57 against a raceway groove to be measured. In order to stably hold themeasuring tool 50, the reference raceway groove is preferably formed on both sides of a groove bottom. - Patent Literature 1:
JPH04-262120A - However, according to the bearing of Patent Literature 1, since each raceway groove of the outer ring is formed only from the groove bottom to the groove shoulder on the one side in the axial direction, the
measuring tool 50 for measuring the dimension between the raceway grooves cannot be stably installed, a measurement value becomes unstable, and it becomes difficult to machine the outer ring having high dimensional accuracy between the raceway grooves. - The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a multi-row bearing and a bearing unit including the multi-row bearing in which an axial dimension between raceway grooves can be accurately and easily measured at a short time, and the raceway grooves can be further machined with high dimensional accuracy.
- The above object of the present invention is achieved by the following configuration [1] relating to a multi-row bearing.
- [1] A multi-row bearing including:
- an inner ring having multiple rows of inner ring raceway grooves;
- an outer ring having multiple rows of outer ring raceway grooves; and
- a plurality of balls disposed between the multiple rows of inner ring raceway grooves and the multiple rows of outer ring raceway grooves,
- wherein the inner ring raceway groove at one end portion in an axial direction is formed over groove shoulders on both sides in the axial direction with respect to a groove bottom,
- wherein the inner ring raceway groove at an intermediate portion in the axial direction is formed over a groove shoulder on one side in the axial direction from a groove bottom,
- wherein the outer ring raceway groove at another end portion in the axial direction is formed over groove shoulders on both sides in the axial direction with respect to a groove bottom, and
- wherein the outer ring raceway groove at the intermediate portion in the axial direction is formed over a groove shoulder on one side in the axial direction from a groove bottom.
The above object of the present invention is achieved by the following configuration [2] relating to a bearing unit. - [2] A bearing unit including: a ball screw mechanism; and
- the multi-row bearing according to the above [1],
- wherein a nut of the ball screw mechanism constitutes the inner ring.
- According to the multi-row bearing of the present invention, the axial dimension between the raceway grooves can be accurately and easily measured at a short time, and accordingly, the raceway grooves of the multi-row bearing having high dimensional accuracy between the raceway grooves and stable quality can be machined. In addition, it is possible to obtain a compact and inexpensive bearing unit that includes the multi-row bearing and can cope with a high load.
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FIG. 1 is a cross-sectional view illustrating a state before a multi-row bearing having three rows of raceway grooves is assembled. -
FIG. 2 is a cross-sectional view illustrating a state after the multi-row bearing illustrated inFIG. 1 is assembled. -
FIG. 3A is a side view of a measuring tool for measuring an axial dimension between raceway grooves of the multi-row bearing, andFIG. 3B is a side view illustrating a state where the axial dimension between the raceway grooves of the multi-row bearing is measured by the measuring tool. -
FIG. 4 is a cross-sectional view illustrating a state before a multi-row bearing having four rows of raceway grooves is assembled. -
FIG. 5 is a cross-sectional view illustrating a state after the multi-row bearing illustrated inFIG. 4 is assembled. - Hereinafter, embodiments of a multi-row bearing according to the present invention will be described in detail with reference to the drawings.
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FIG. 1 is a cross-sectional view illustrating a state before a multi-row bearing according to a first embodiment of the present invention is assembled, andFIG. 2 is a cross-sectional view illustrating a state after the multi-row bearing is assembled. In the following description, a left direction and a right direction in the drawings are referred to as one side and the other side, respectively. - As illustrated in
FIGS. 1 and2 , abearing unit 100 according to the first embodiment includes a multi-row bearing 10 and aball screw mechanism 40 using aninner ring 30 of the multi-row bearing 10 as a nut. - The multi-row bearing 10 according to the present embodiment includes an
outer ring 20 having three rows of outerring raceway grooves inner ring 30 having three rows of innerring raceway grooves balls 45 disposed between the outerring raceway grooves ring raceway grooves ring raceway grooves - The outer
ring raceway groove 21a formed at an end portion on the other side in an axial direction of theouter ring 20 is formed over groove shoulders on both sides in the axial direction. Specifically, the outerring raceway groove 21a is formed in left-right line symmetry with respect to a groove bottom. - In addition, the two outer
ring raceway grooves outer ring 20 are each formed over a groove shoulder on the one side (the other side) in the axial direction from a groove bottom. Specifically, theraceway grooves ring raceway groove 21a has a raceway groove having a substantially semicircular cross section, and the outerring raceway grooves outer ring 20. - A
cylindrical surface 21e continuous from the groove bottom of the outerring raceway groove 21b is formed between the outerring raceway groove 21b and the outerring raceway groove 21c. Further, acylindrical surface 21f continuous from the groove bottom of the outerring raceway groove 21c is also formed on one side in the axial direction of the outerring raceway groove 21c. An inner diameter of the groove bottom of the outerring raceway groove 21b and an inner diameter of thecylindrical surface 21e, and an inner diameter of the groove bottom of the outerring raceway groove 21c and an inner diameter of thecylindrical surface 21f are substantially the same. Thecylindrical surface 21e is provided with anopening portion 22 penetrating in a radial direction. The inner diameters of thecylindrical surfaces ring raceway grooves cylindrical surfaces - The
inner ring 30 is also a nut of theball screw mechanism 40 as will be described later, and is a divided inner ring including a substantially bottomed cylindrical inner ringmain body 31 that is long in the axial direction and has a bottomedhole 34 having abottom portion 33 at the end portion on the other side, and apressing lid 32. The innerring raceway groove 31a formed at end portion on one side of the inner ringmain body 31 is formed over groove shoulders on both sides in the axial direction. Specifically, the innerring raceway groove 31a is formed in left-right line symmetry with respect to a groove bottom. - The inner
ring raceway groove 31b formed at an intermediate portion in the axial direction of theinner ring 30 extends from a groove bottom to the groove shoulder on the one side (one side) in the axial direction. Specifically, the raceway groove is formed only on one side with respect to the groove bottom. Acylindrical surface 31f continuous from the groove bottom of the innerring raceway groove 3 1b is formed on the other side of the innerring raceway groove 31b. An outer diameter of the groove bottom of the innerring raceway groove 31b and an outer diameter of thecylindrical surface 31f are substantially the same. The inner diameter of thecylindrical surface 31f may be different from the inner diameter of the innerring raceway groove 31b as long as thecylindrical surface 31f does not interfere with balls when the balls are assembled as described later. - The
pressing lid 32 is a member fixed to the inner ringmain body 31 to form the innerring raceway groove 31c, and a raceway groove having a substantially 1/4 circular cross section and serving as the innerring raceway groove 31c is formed in an outer diameter corner portion on one side. Further, the pressinglid 32 is provided with ascrew hole 36 through which a bolt (not illustrated) for screwing into afemale screw 35 provided at thebottom portion 33 of the inner ringmain body 31 to fix thepressing lid 32 to the inner ringmain body 31 is inserted. - Although not illustrated in detail, a ball screw groove 41 (nut-side ball screw groove) of the
ball screw mechanism 40 is formed on an inner peripheral surface of the bottomedhole 34 of the inner ringmain body 31, and aball screw shaft 43 formed with a ball screw groove 42 (screw shaft-side ball screw groove) formed on an outer peripheral surface thereof is rotatably accommodated in the bottomedhole 34. A plurality of balls (not illustrated) are disposed between theball screw groove 41 of the inner ringmain body 31, that is, the nut and theball screw groove 42 of theball screw shaft 43 so as to be freely rotatable therebetween. - That is, the
bearing unit 100 is formed by combining theball screw mechanism 40 including the inner ringmain body 31, which is provided with theball screw groove 41 on the inner peripheral surface and functions as the nut of theball screw mechanism 40, theball screw shaft 43, and the balls (not illustrated) with themulti-row bearing 10. - Next, a method for assembling the
outer ring 20, theinner ring 30, and the plurality ofballs 45 will be described. First, as illustrated inFIG. 1 , theouter ring 20 is placed on theinner ring 30 in a state of being slightly shifted to the other side. In this state, the openingportion 22 of theouter ring 20 is positioned corresponding to the innerring raceway groove 31b. - Then, the plurality of
balls 45 are loaded between the innerring raceway groove 31a and thecylindrical surface 21f of theouter ring 20 from one side. The plurality ofballs 45 are loaded between the innerring raceway groove 31b and thecylindrical surface 21e from the openingportion 22. Further, the plurality ofballs 45 are loaded into the outerring raceway groove 21a from the other side, and are pressed by the pressinglid 32. - Next, as illustrated in
FIG. 2 , theouter ring 20 is slid to one side together with thepressing lid 32, gaps between theballs 45 and the outerring raceway groove 21a and the innerring raceway groove 31c are adjusted to a predetermined value by the pressinglid 32, a bolt (not illustrated) inserted into thescrew hole 36 of thepressing lid 32 is screwed into thefemale screw 35, and thepressing lid 32 is fixed to the inner ringmain body 31. Accordingly, the plurality ofballs 45 are disposed between the respective raceway grooves, that is, between the innerring raceway groove 31a and the outerring raceway groove 21c, between the innerring raceway groove 31b and the outerring raceway groove 21b, and between the innerring raceway groove 31c and the outerring raceway groove 21a so as to be rollable therebetween, whereby the multi-row bearing 10 of three rows are assembled. - Although not illustrated in detail, when in a state where the rotation of one (for example, the ball screw shaft 43) of the
inner ring 30, that is, the nut or theball screw shaft 43 is restrained, the other one (for example, the inner ring 30) is rotationally driven, theball screw shaft 43 moves in the axial direction relative to theinner ring 30. Here, when a load toward the other side in the axial direction is applied to an end portion of theball screw shaft 43 on the one side, a load P indicated by an arrow in the drawing acts on theball screw shaft 43. Since the load P is received by themulti-row bearing 10 having multiple rows of raceway grooves, the large load P can be supported. - In order to smoothly operate the
multi-row bearing 10 configured as described above, it is required that axial positions of three rows of the outerring raceway grooves ring raceway grooves ring raceway grooves ring raceway grooves multi-row bearing 10. - Since the inner
ring raceway grooves inner ring 31, comparative measurement and machining are easy, but since the outerring raceway grooves outer ring 20, the outerring raceway grooves - The axial dimension between the raceway grooves is measured by a
dedicated measuring tool 50 as illustrated inFIGS. 3A and 3B . Hereinafter, a case where an axial dimension between raceway grooves of theouter ring 20 is measured will be described as an example. - As illustrated in
FIG. 3A , the measuringtool 50 includes a fixedarm 52 fixed to asupport shaft 51, amovable arm 53 swingable about thesupport shaft 51, and a measuringarm 54 provided to be slidable with respect to the fixedarm 52.Steel balls balls 45 used in themulti-row bearing 10 are attached to distal ends of the fixedarm 52 and themovable arm 53, and a gauge head (steel ball) 57 having the same size as theballs 45 used in themulti-row bearing 10 is similarly attached to a distal end of the measuringarm 54. - By swinging the
movable arm 53 with respect to the fixedarm 52, an interval between thesteel balls outer ring 20. Then, as illustrated inFIG. 3B , thesteel balls arm 52 and themovable arm 53 are fitted into the pair of outerring raceway grooves 21a of theouter ring 20 facing each other, and the measuringtool 50 is stably held. That is, the outerring raceway groove 21a of theouter ring 20 whose raceway groove is formed on both sides with respect to the groove bottom serves as a reference groove for measuring a distance between the raceway grooves. - In a state where the measuring
tool 50 is stably held by theouter ring 20, themovable arm 53 is extended and contracted in an arrow direction to engage thegauge head 57 with the outerring raceway groove arm 54. In this way, by measuring the axial distances of the remaining outerring raceway grooves ring raceway groove 21a whose raceway groove is formed on both sides with respect to the groove bottom, the outerring raceway grooves ring raceway groove 21a. - Accordingly, it is not necessary to remove the
outer ring 20 during machining from a machining device every time the axial dimension between the raceway grooves is measured, working efficiency is improved, and the outer ring raceway groove can be accurately machined. - Next, the
multi-row bearing 10 according to a second embodiment of the present invention will be described with reference toFIGS. 4 and5 . In themulti-row bearing 10 according to the second embodiment, four rows of outerring raceway grooves outer ring 20, and four rows of innerring raceway grooves inner ring 30 so as to face the outerring raceway grooves - Among the outer
ring raceway grooves outer ring 20, the outerring raceway grooves ring raceway grooves cylindrical surfaces 21e continuous from the groove bottoms of the outerring raceway grooves cylindrical surfaces 21e are provided with the openingportions 22 penetrating in the radial direction. - Also in the
multi-row bearing 10 according to the second embodiment, the axial dimension between the raceway grooves can be accurately measured at a short time by the measuringtool 50 illustrated inFIG. 3 with reference to the outerring raceway groove 21a. Accordingly, the other outerring raceway grooves ring raceway groove 21a. - Although not shown in the drawings, a method for assembling the
outer ring 20, theinner ring 30, and the plurality ofballs 45 is the same as that of themulti-row bearing 10 according to the first embodiment in that theball screw mechanism 40 is configured by using theinner ring 30 as the nut and disposing theball screw shaft 43 inside the nut. In this case, since themulti-row bearing 10 according to the second embodiment has four rows of raceway grooves, it is possible to support a larger load than themulti-row bearing 10 according to the first embodiment. - Since the other parts are the same as those of the
multi-row bearing 10 according to the first embodiment of the present invention, the same parts are denoted by the same reference numerals or corresponding reference numerals, and the description thereof will be simplified or omitted. - The present invention is not limited to the embodiments described above, and modifications, improvements, and the like can be appropriately made.
- As described above, the following matters are disclosed in the present specification.
- (1) A multi-row bearing including:
- an inner ring having multiple rows of inner ring raceway grooves;
- an outer ring having multiple rows of outer ring raceway grooves; and
- a plurality of balls disposed between the multiple rows of inner ring raceway grooves and the multiple rows of outer ring raceway grooves,
- wherein the inner ring raceway groove at one end portion in an axial direction is formed over groove shoulders on both sides in the axial direction with respect to a groove bottom,
- wherein the inner ring raceway groove at an intermediate portion in the axial direction is formed over a groove shoulder on one side in the axial direction from a groove bottom,
- wherein the outer ring raceway groove at another end portion in the axial direction is formed over groove shoulders on both sides in the axial direction with respect to a groove bottom, and
- wherein the outer ring raceway groove at the intermediate portion in the axial direction is formed over a groove shoulder on one side in the axial direction from a groove bottom.
- According to this configuration, the axial dimension between the raceway grooves can be accurately and easily measured at a short time, and accordingly, the raceway grooves of the multi-row bearing having high dimensional accuracy between the raceway grooves and stable quality can be machined.
- (2) The multi-row bearing according to (1),
wherein an opening portion penetrating in a radial direction is provided in a cylindrical surface of the outer ring in a row of the intermediate portion in the axial direction.
According to this configuration, the balls can be easily loaded into the raceway groove at the intermediate portion in the axial direction from the opening portion, and the multi-row bearing can be easily assembled. - (3) The multi-row bearing according to (1) or (2),
- wherein the outer ring raceway groove at the intermediate portion in the axial direction has a cylindrical surface on a side opposite to the groove shoulder with respect to the groove bottom, and
- wherein the inner ring raceway groove at the intermediate portion in the axial direction has a cylindrical surface on a side opposite to the groove shoulder with respect to the groove bottom.
- According to this configuration, since the outer ring is slid in the axial direction, the balls loaded from the opening portion can be held between the outer ring raceway groove and the inner ring raceway groove.
- (4) The multi-row bearing according to any one of (1) to (3),
wherein the inner ring raceway groove at the other end portion in the axial direction is formed by a divided inner ring.
According to this configuration, it is possible to easily form the inner ring raceway formed at the end portion on the other side of the multi-row bearing. - (5) A bearing unit including:
- a ball screw mechanism; and
- the multi-row bearing according to any one of 1 to 4,
- wherein a nut of the ball screw mechanism constitutes the inner ring.
- According to this configuration, since the multi-row bearing and the ball screw mechanism are combined, it is possible to configure the bearing unit that is movable in the axial direction and supports a large thrust load.
- Although various embodiments have been described above with reference to the drawings, the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications may be conceived within the scope of the claims, and it is also understood that the various changes and modifications belong to the technical scope of the present invention. In addition, constituent elements in the embodiments described above may be combined freely within a range not departing from the spirit of the present invention.
- The present application is based on a Japanese patent application (
Japanese Patent Application No. 2021-062354) filed on March 31, 2021 -
- 10 multi-row bearing
- 20 outer ring
- 21a to 21d outer ring raceway groove
- 21e, 21f, 31f cylindrical surface
- 22 opening portion
- 30 inner ring (nut of ball screw mechanism)
- 31a to 31d inner ring raceway groove
- 32 pressing lid (divided inner ring)
- 40 ball screw mechanism
- 45 ball
- 100 bearing unit
Claims (5)
- A multi-row bearing comprising:an inner ring having multiple rows of inner ring raceway grooves;an outer ring having multiple rows of outer ring raceway grooves; anda plurality of balls disposed between the multiple rows of inner ring raceway grooves and the multiple rows of outer ring raceway grooves,wherein the inner ring raceway groove at one end portion in an axial direction is formed over groove shoulders on both sides in the axial direction with respect to a groove bottom,wherein the inner ring raceway groove at an intermediate portion in the axial direction is formed over a groove shoulder on one side in the axial direction from a groove bottom,wherein the outer ring raceway groove at another end portion in the axial direction is formed over groove shoulders on both sides in the axial direction with respect to a groove bottom, andwherein the outer ring raceway groove at the intermediate portion in the axial direction is formed over a groove shoulder on one side in the axial direction from a groove bottom.
- The multi-row bearing according to claim 1,
wherein an opening portion penetrating in a radial direction is provided in a cylindrical surface of the outer ring in a row of the intermediate portion in the axial direction. - The multi-row bearing according to claim 1 or 2,wherein the outer ring raceway groove at the intermediate portion in the axial direction has a cylindrical surface on a side opposite to the groove shoulder with respect to the groove bottom, andwherein the inner ring raceway groove at the intermediate portion in the axial direction has a cylindrical surface on a side opposite to the groove shoulder with respect to the groove bottom.
- The multi-row bearing according to any one of claims 1 to 3,
wherein the inner ring raceway groove at the other end portion in the axial direction is formed by a divided inner ring. - A bearing unit comprising:a ball screw mechanism; andthe multi-row bearing according to any one of claims 1 to 4,wherein a nut of the ball screw mechanism constitutes the inner ring.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2021062354 | 2021-03-31 | ||
PCT/JP2022/015548 WO2022210734A1 (en) | 2021-03-31 | 2022-03-29 | Multi-row bearing and bearing unit |
Publications (1)
Publication Number | Publication Date |
---|---|
EP4317720A1 true EP4317720A1 (en) | 2024-02-07 |
Family
ID=83456262
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP22780945.6A Pending EP4317720A1 (en) | 2021-03-31 | 2022-03-29 | Multi-row bearing and bearing unit |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP4317720A1 (en) |
JP (1) | JPWO2022210734A1 (en) |
CN (1) | CN117157466A (en) |
TW (1) | TW202242274A (en) |
WO (1) | WO2022210734A1 (en) |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61166228U (en) * | 1985-04-04 | 1986-10-15 | ||
JP2001163231A (en) * | 1999-09-30 | 2001-06-19 | Ntn Corp | Motor-driven power steering device |
JP2002039202A (en) * | 2000-07-19 | 2002-02-06 | Thk Co Ltd | Rolling rotational bearing |
JP7433588B2 (en) | 2019-10-16 | 2024-02-20 | エス・ピー・ジーテクノ株式会社 | Cylindrical porous membrane module |
-
2022
- 2022-03-29 WO PCT/JP2022/015548 patent/WO2022210734A1/en active Application Filing
- 2022-03-29 JP JP2023511391A patent/JPWO2022210734A1/ja active Pending
- 2022-03-29 CN CN202280026382.8A patent/CN117157466A/en active Pending
- 2022-03-29 EP EP22780945.6A patent/EP4317720A1/en active Pending
- 2022-03-31 TW TW111112506A patent/TW202242274A/en unknown
Also Published As
Publication number | Publication date |
---|---|
JPWO2022210734A1 (en) | 2022-10-06 |
TW202242274A (en) | 2022-11-01 |
CN117157466A (en) | 2023-12-01 |
WO2022210734A1 (en) | 2022-10-06 |
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